I use Fullscreen Mode when I read comics on Kindle4.
But when the kindle goes into screensaver mode and I wake it up again the kindle is no longer in Full Screen Mode so I have to Disable Full Screen Mode and then Enable Full Screen Mode again in order to get Full Screen again.
Some one told me that there's a hotkey to enable/disable full screen mode. 'f'.
But that method doesn't working on my Kindle4.